Boat bumper assembly



FIG. 1 is an elevational view of the boat bumper assembly according to our new design;

FIG. 2 is a side view thereof;

FIG. 3 is an environmental perspective view thereof; and,

FIG. 4 is a top view thereof.

The broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a boat bumper assembly, as shown and described. 